xml-dev - RE: [x3d-contributors] geometry first, MathML, CAD, etc

["Paul Fishwick" <fishwick@cise.ufl.edu>]

Jean-Marc:

   We have similar needs in our project. For example, we may wish to employ

CML (Chemical Markup Language) in the rendering of molecules being rendered

for molecular dynamics purposes. When Henry Ford built his first automobile,

my guess is that he had to hand-construct many of the components since there

did not exist a supply-chain for carburetors, brakes, wheels and so forth. As time

progressed, these supply-chains multiplied in what might be called a Darwinian

or Capitalistic evolution---thus, providing ways to make automobiles whose

components are now "outsourced" to other companies, forming a huge tree or graph

of industrialization.

  X3D is similar. There has to be a seed, or coherent entity where we begin. To take

the analogy with car construction, it may be that someone develops GML (geometry

markup language) or LML (light-modeling markup language). Furthermore, these

languages may fit well into what we need when building worlds. One of two things

can happen: 1) we can grow X3D to depend exclusively on these MLs, or 2) these

MLs with their associated DTDs would accompany any and all worlds that depend

upon them. In the first case, this is similar to Ford acquiring the company that

makes carburetors and integrating it within his own company. Option 2 seems like

the more logical approach where we (the content authors) use whatever MLs we

like in our worlds; we pick and choose which MLs can be used together to get

our task done. Presumably, with XML on the move, browser techniques will exist

that allow DTDs and style sheets to be automatically downloaded without burdening

the user of your software. Everyone is a winner. You get to use MathML but the use of

MathML is not directly incorporated within X3D. In this sense X3D is not monolithic -- it

is Henry's first crack at a small but usable car. This suggests that X3D will change

over time as new MLs evolve to make it smaller and more efficient, and furthermore,

more accommodating to new XML components that will take the place of older X3D

components that are not as robust.

 I have my fingers crossed that multiple MLs can be  used together :)

 

-paul

 

-----Original Message-----
From: x3d-contributors-approval@web3d.org [mailto:x3d-contributors-approval@web3d.org]On Behalf Of Jean-Marc Vanel
Sent: Wednesday, March 01, 2000 2:44 AM
To: xml-dev@xml.org; Patrick Laug; Amine Hassim; x3d-contributors@web3d.org; Frederic ABIVEN; Jean Marc VANEL; TDWG-SDD@USOBI.ORG
Subject: [x3d-contributors] geometry first, MathML, CAD, etc

Hello

I have followed the debates about VRML/X3D for weeks, and it's time to speak.

The aim of our project is to make botanical data available on Internet, including 3D images.

We need a compact, non proprietary, preferably XML, clean definition for complex 3D geometries.

It seems that a representation both compact and flexible should be based on  mathematics. VRML's cones and cylinders are just special cases of intersections of volumes defined by equations:
f(x,y,z)>=0

NURBS and Beziers patches are just special cases of surfaces defined by 3 functions R2 ---> R3
(u,v) ---> (X(u,v),Y(u,v),Z(u,v))

A solution is to use the content part of MathML. I have reviewed it: it has the desired capabilities, i.e. allows to define functions and sets, it is XML. Certainly only a subset of MathML is needed: n-dimentional geometry, n>3 is not relevant. On the other hand, some geometrical primitives could be added :
- convex hulls,
- recursive constructs like fractals and L-systems,
- transforms, deformations, parametrization, movement
 

My second point is about modular schemas versus monolythic Schemas. X3D is a very "good" example of monolythic DTD. NOTHING is taken from the XML world outside X3D.

It seems that Virtual Reality involves several layers that can be used and designed independently:
- volumic objects definition (see above)
- colors and textures on volumic objects
- behavior of volumic objects among them (contact, glued or sliding, rotating, interpenetrable, etc)
- behavior of volumic objects with User Interface
- a scene as composite Design pattern of volumic objects
- light sources
- scenarios (time-dependant aspect )
- sounds

Conclusion:

This need for a compact, non proprietary, preferably XML, clean definition for complex 3D geometries is common with other important domains:
- Computer Aided Design
- Architecture
- simulation in mechanics, physics, and biology

CAD is a very important field that has currently no XML non-proprietary language. It seems that the proposed solution could bring an interesting synergy able to speed up developments, together with a better design. And also a common subset for CAD and Virtual Reality will bring new possibilities to exchange data.
A well-designed model and XML syntax for virtual reality could also be used for cartoons and video games.
 

--
<person>
  <first_name>Jean-Marc</first_name>
  <name>Vanel</name>
  <project>Worlwide Botanical Knowledge Base -
      making botany available on Internet
    <a href="http://wwbota.free.fr/" >site</a>
  </project>
  <homePage>http://jmvanel.free.fr/</homePage>
  <a href="mailto:jmvanel@free.fr">mail (eventually put "wwbota" in subject to route your mail in relevant folder)</a>
</person>